Piano hammer forming machine



P 27, 2- r w. .1. PFRIEMER 1,379,454

PIANO HAMMER FORMING MACHINE Filed Jan. 23; 1931- a Shqets-Shet 1wnmzssr-zs 5:402 750 w WZ/[am rzihzer ATTORNEY P' 91 w. J. PFRIEMER1,879,464

PIANO HAMMER FORMING MACHINE Filed Jan. 23, 1931 I5 Sheets-Sheet 2 F x I6' W IT lTII 7y INVENTOR WITNESSES WZZZmm If meme;-

1x BY ATTORNEY p 1932- w. J. PFRIEMER 1,879,464

PIANO HAMMER FORMING MACHINE Fi led Jan. 25, 1931 s Sheets-Sheet sINVENTQR WITNESSES I Wig/67716! ATTORNEY Patented Sept. 27, 1932,

UNITED STATES ATENT" OFFICE WILLIAM. J. PFRIEMER, OF BELVIDERE, NEWJERSEY PIANO HAMMER romaine MACHINE 7 Application filed January 23,1931. Serial No. 510,838.

vide a piano hammer forming machine.

wherein piano hammer strips may be made of difierenthardnesses so thatthe hammers when placed in a piano may correspond with the particularwork they are to do.

A further object, more specifically, is to provide a piano hammerforming machine wherein the parts of the piano strip are pressed firmlytogether by suitable dies and associated with means for locking the diesin their clamped position so that they may be removed from the machineand a new one substituted, said removal not interfering with the fixedclamping position of the various dies.

An additional object of the invention is to provide a machine which willpress a section or an entire piano hammer strip into proper shape, thesame being associated with dies and locking means which are removablefrom the machine after having been brought to a locking position,whereby the successive sections or complete strip may be formed withoutwaiting for the glue to dry.

In the accompanying drawings Figure 1 is a front view of a piano hammerforming machine disclosing an embodiment of the invention;

Figure 2 is a side view of the machine shown in Figure 1; v

Figure 3 is a fragmentary view showing the dies and associated partsillustrated in Figure 1, but illustrating the same in a closed andlocked position ready to be removed from the pressing machine;

Figure 4 is a view similar to Figure 3 but showing the parts about to beremoved;

Figure 5 is a perspective view of the dies, locks therefor, and hammerstrip or hammer section shown in Figure .4, the same being removed.

Referring to the accompanying drawings by numerals, 1 indicates theframe of the pressing machine which may be provided with suitable bars,arms and other members to carry the various moving parts. Asillustratedin Figures 1 and 2, frame 1 includes a pair of crane members 2which inturn carry therespective sliding threaded compression rods 3. As both ofthese rods and associated parts are identical, the description of onewill apply to both. 'As illustrated in Figure 2 a link 4-is piv ,otallymounted at 5 on the crane member 2, and pivotally connected at 6'with alever 7.

The pin or other means 8 pivotally connects lever 7 with the upper endof rod-3, while a pin or other means 9 pivotally connects one end oflever 7 with a piston rod 10 of a suitable piston arranged in the aircylinder 11; This cylinder has ports at points 12 and 13, said portsbeing alternately outlet and in let ports. Port 12 is connected by pipe14 witha foot valve 15, while port 13is connected by pipe 16 to footvalve 15. An air supply pipe 17 isalso connected to the foot valve 15,said pipe ,17 being connected to an air compression pump or tank where acontinuous supply of compressed air is provided. During theoperation ofthe machine, as hereinafter described, it will be noted that air passingfrom pipe 17 .will pass through suitable ports in the foot valve 15 andwill alternately pass through pipes 14 and 16 according to the directionof movement of the piston rod 10. For instance, by depressing the footpedal 18 air will be admitted from pipe 17 to pipe 14. When this occursair will pass into the bottom of cylinder 11 and the. air 35 above thepiston will pass out of the top through port 12 and pipe 14, there beinga suitable exhaust valve in the valve 15. Valve 15 is so constructedthat after having been once depressed it remains in that position untilmoved upwardly to a central or, neutral position, .or until the footpedal 19 is de pressed, whereupon the reverse action takes place,namely, air will pass from pipe 17 to pipe 14 and from thence intocylinder 11 at the top, whereby the piston rod 10 and associated partswill be moved downwardly so that the parts will assume the positionshown in Figure 2.

While this is taking place air will be exi reducing valvesare adjustedaccordingly and hausted through pipe 16. The foot valve 15 is an old andwell known type and therefore the details thereof have not been setforth in the drawings. The particular valve 15 disclosed in the drawingsis a Logan foot control operating valve known as Model H, andmanufactured by the Logansport Machine Co. of KLogansport, Indiana.'This valve operates as above set forth. The desirability of using thevalve just mentioned is that when one pedal is forced down' the pistonrod 10 is moved upwardly and held upwardly, and moved down and held downwardly until released, .when the other pedal is operated. Thetwocylinders 11 are'con-' nected together as shown in Figure 1 so as tobe operated simultaneouslyby the single foot pedal 15. -Variations inthe pressure in the two cylinders is secured through the use of reducingvalves'16 and 16" located in air feed lines of the respective cylinders-By reason of this structure,-as one cylinder is to operate at a givenpressure and the other cylinderat'a slightly higher pressure. The, two

then will automatically supply the pressure desired from thesamesource.of compressed air supply.

In the accompanyingdrawings the strip i 20 is shown as being 14 incheslong, but it length was usually about 40 inches and in view of the factthat it was pressed into a die all at one time, the resulting structurehad the same characteristics throughout due to the rigid and inflexiblepressure of the dies used. 7 1

By providing three sections for a piano one section may be made so thatthe hammer heads will be hard, a second section may be made so 7 thatthe heads will be of a medium hardness,

and the third section so that the heads willbe comparatively yielding,and each section in varying'degrees from one end to the other. In thisway the various hammer heads provided for a piano and cut from thesethree sections will answer the requirements of musicians and will causethe strings of a piano to vibrate in a proper manner and with propertone effects. I l

Asshown in Figure 1 the respective rods 3 slide loosely through sleeves22 and carry stop nuts 21 for limiting the movement of the rods 'in onedirection. The lower end of each of the rods 3 is supplied with a link23. Each of these links has its lower end pivotally connected with a bar24 formed with a depending flange 25. The formation of this flange 25results in a shoulder 26 and also a notch 27. Notch 27 is adapted toreceive a clamping plate 28 which is suspended by pins 29, said platebeing adapted to clamp the base 30 of the piano hammer section 31 firmlyin the notch. This is accomplished by reason of a swinging catch 32 ateach end of the bar 24, said catches having suitably formed slots 33adapted to fit over the respective pins 34 to draw the clamping plate 28tightly against the base 30, as illustrated in Figure 3. By reasonof-these catches 32 base 30 may be quickly and easily released at anytime.

As shown in the drawings the under felt 35 has been secured to thewooden strip and the outer felt 36 is about to be applied, or isapplied, as shown in Figures 3 to 5, inclusive. However, as shown inthese figures the glue is not yet dry and consequently the dies 37 and38 are held rigidly in their clamped position by suitable cams 39.

In the formation of the complete hammer head section the parts arepositioned as shown in Figures 1 and 2 and one pedal of the foot valve15 is operated, whereupon air at a certain pressure isdirected into thelower part of each of the cylinders 11. This will cause both of the rods3 to move downwardly and move at the same pressure when the same airsupply is being used. This downward pressure in the two cylinders 11 isregulated to a predetermined degree by the reducing valves 16 and 16".In the feed lines of the respective cylinders one of the reducing valves16 or 16 is set for a lower pressure and the reducing valve so set willfirst out off the air supply for its cylinder at the degree of pressurefor which it is set and then the other cylinder with a higher degree ofpressure will shutoif the supply as soon as the higher pressure has beenreached. If desired, gauges could be connected with the respective pipesto indicate or showthe degree of pressure in each cylinder. A die 40 isarranged immediately beneath the center of the upper felt 36 and thisdie is formed with a depressed portion 41, whereby part of the felt 36will be pressed into the depression 41 and the ends 42 and 43 will betilted upwardly appreciably.

From Figure 1 it will be seen that springs 44 and 45 are connected tothe respective rods 3 and to the bar 24 to assist in centering the bar24 but will not prevent the respective rods 3 functioning to exert thedesired pressure on the outer felt 36. It will thus be noted thatsprings 44 and 45 are anchored to the lower ends of the rods 3 and arealso anchored to the bar 24. This will prevent any accidental swingingmovement of this bar. If it were not for these springs, the links23would allow a swinging movement before the parts contacted with thefelt 3.6. These" springs-preventa longi tudinal movement of the bar 24but will not prevent the rods 3 to function as described.

After the inner felt and the wooden support therefor have been moveddownwardly,

as above described, the respective pedals 46 and 47 are depressed,whereupon mechanism outer surface of the outer felt 36 in the cor-" rectshape, as shown in Figures 3 and 4. As these diesmovetoward each otherunder pressure above specified, which may be lbs. or more, the cams orwedge cams 39 will automatically function to lock the dies againstreturn movement. Each of these cams is formed as shown in Figure 4 andconsist of a table-shaped body 48 and 2. turned up end 49 associatedwith a spring 50, which spring gives the cams a tendency to moveinwardlyagainst the inclined or cam surface 51 of the die 38. Die 37 is securedby a bolt, rivet or other means 52 rigidly to the respective bars 53 and54. After the parts have been moved to the clamped position, as shown inFigure 3, the dies cannot be retracted until the cams 39 have beenpulled outwardly. :By reason of this fact the dies are locked togetherand the next operation is to release the catches 32, as shown in Figure4, whereupon the clamping plate 28 will become loose. Dies 37 and 38,and the piano hammer. section and associated parts are then bodilyremoved and laid aside, as shown in Figure 5. They are left in thisposition for six hours or longer to permit the adhesive to dry.

Heretofore the entire clamping operation used in clamping the partstogether necessitated allowing theparts to remain together so that onlya few hammer head strips could be made in a day by a given machine. Bythe operation just described a large number may be made in one day. i Infact, the operation just described can be done in a few moments and thenthe complete strip laid asideuntil it is completely dry, after which itis cut into the desired lengths to produce the desired hammer heads.

The air in cylinders 11 is preferably at a considerably higher pressurethan in the cyl-' inders 54 and 55. The air pressure in cylinders 54 and55 produces a constant lateral pressure against the head being formed,

while the difference in pressure in the respective cylinders 11 causes avertical pressure which is greater at one end than at the other in orderto secure different degrees of hard ness in the finished head. The footvalve 46 is similar to the foot valve 15 exceptthat it has only onepedal 47 because the cylinders 54 and 55 automatically exhaust when thepedals are released. The valve 46 may be of any desired. kind toaccomplish this result a but thatshown in the accompanying drawings isthe Logan foot'controlled operating valve, Model G, manufactured by theL0". gansport Machine Company of Logansport, Indiana. WVhen the pedal 47is depressed air will be supplied through air supply pipe 58 to therespective inlet ports 60 and 61. Pipe 58 may be connectedtothe samesupply that, the pipe 17 is connected or may be connected to a differentsupply. It will be understood that piston rods-56. and 57 are connectedto.

suitable pistons adapted. to' reciprocate/in cylinders 54 and 55..Piston rods 56 and 57 are provided each with abifurcated end 62 whichcarries a. pivotal pin 63, while on this pin are pivotally mounted links64 :and 65. The upper end of these links are respectively connected tothelower ends of the levers 66 and 67, and these levers arepivotallymounted on frame 1 at points 68 and 69. The ex treme upper ends oflevers 66 and 67 are provided with slots 70 and 71accommodating therespective pins and 81, these pins ex tending through the respectivesliding blocks 82 and 83, said blocks beingslidingly dovetailed in thesupporting block 84 which is preferably rigidly secured to frame 1.

From F igure2 it will be seen that the blocks 82 and 83 are notched orpartly bifurcated,' and the ends of'the levers 66 and 67 extend intothese notches or partial bifurcations. In this way the levers 66 and 67may move the blocks 82 and 83 toward and from each other andconsequently may move the dies 37 and 38 to a clamping position as shownin Figure 3. It is tobe understood that when pedal 46 is lowered it isheld down by'the feet of the operator, but this condition is onlytemporary because the parts will quickly move the dies over to theclamping position and the cams 39 will lock the dies against returnmovement. As soon as the dies have been moved over to their correctclamping position the piston rods 56 and 57 are released andautomatically the foot valve 46 will permit the air to escape throughthe ports 60 and 61 and permit air to enter the cylinders through ports85 and 86. i

' By this structure the blocks 82 and 83 are positively moved to theposition shown in Figure 2. Ainewset of dies 37 and 38 then may be addedand the operation repeated. From Figure 2 it will be noted that thecylinders 11 are pivotally mounted so as to swing as the leverandassociated parts operate. It will, of course, be understood that theglue or other adhesive is applied for holding the inner felt 35 in placeand also for holding the outer felt 36 in place after it has been foldedand pressed and leftto dry, as illustrated in Figure 5. V

j What I claim is- 1. A" piano hammer forming machine including a pairof clamping dies for clamping the heads of the piano hammer strip, saiddies being positioned to slide toward and from each other, sliding wedgecams for locking'said dies in clamping position, and means'for movingthe dies to a clamping position, said wedge cams automatically engagingand locking said dies against a return movement, said wedge camsfunctioning at all times during the movement of said dies, said dies1.being bodily removable from the last mentioned means while in aclamping position, whereby the operation may be repeated in quicksuccession.

2. In a device-for forming piano hammer head strips including a'pair ofsliding-dies for clamping the hammer head strips, guiding bars forguiding the sliding movement of said dies, a cam for each guiding barcarried by one of said'dies for locking the dies in a clampingposition,said wedge cams functioning at any point along the respectiveguide bars, a pair of sliding iaws for moving the dies to a clampingposition while the dies are functioning, said dies being bodilyremovable with thestrip after said dies have been moved to a clampingposition and while in a clamping position. i

3. A piano hammer forming machine including a press formed with avertical recip rocating power actuated bar and a plurality of pairs ofhorizontally sliding power actuated clamping members, means for clampingthe base of a piano strip in said vertical bar, a pair of diespositioned to be moved toward each other by said clamping members,whereby an outer felt may be clamped tightly against a proper place onsaid base, a pair of guide bars for said dies, one of said dies beingconnected to said guide bars while the other die is slidable thereon,and means connected with the die which is slidably mounted on the guidebar for automatically locking said die. against a return movement, saiddies and means for clamping the same together being bodily removablewith the piano hammer head strip while in a clamping position.

4. In a piano hammer forming machine a press formed with means forreceiving and moving a piano hammer head strip base with its inner feltto a given position, a pair of removable dies, a pair of guiding barseach connected at one end to one of said dies and each slidinglyextending through the other die, the said last mentioned die beinghollow, means operated by the press for moving the dies to a clampingposition, said dies acting to clamp the outer felt around said innerfelt, said dies being bodily removable when said clamping means has beenreleased and while intheir clamping position, and cam means carried bysaid hollow die and project-' ing therein for automatically locking saiddies in theclamping position i 4 5.- In a piano hammer forming machine apress provided with means for removably receiving the wooden base of apiano hammer headstrip, a pair of dies removably mounted on the machinefor clamping the outer felt in position against said base, a pair ofsliding blocks operated by said machine for moving said dies toaclamping position, a pair of guiding bars for said dies, one of saiddies being hollow and cam means for automatically locking said dies inclamping position whereby when said blocks'have been moved to a releasedposition and said base released from said press, said dies, felts andbase are capable of being removed while the dies are in their lockedposition and placed at one side until the parts have set said cam meansincluding a cam slidingly mounted on each of said guiding bars with oneend extending into said hollow die and a spring acting on each cam forpressing the cam continually against the hollow die for locking the diesagainst a return movement.

6. A piano hammer forming machine including a press provided with aplurality of horizontally moving clamping blocks, and a pair ofvertically moving power rods, means carried by the power rods forremovably receiving the base of a piano hammer head strip, a diearranged beneath said piano hammer head strip, said die being adapted toreceive an outer felt to be applied to said base, said power rods actingto move said base so as to compress to a desired extent the central partof said outer felt, a pair of dies positioned so that onedie will be oneach side of said outer felt, one of said pair of dies being hollow,said dies being slidable whereby when said clamping blocks are movedtoward each other said dies will be moved toward each other accordinglyand will fold and press said outer felt against said base, and means forlocking said dies in their clamping position, said dies being bodilyremovable while in their clamping position whereby when said base isreleased the piano hammerhead strip and dies may be moved to one sideuntil the felt has properly set, said means for locking said diesincluding a pair of sliding cams continually projecting into said hollowdie, each of said cams having a turned-up portion within said hollow dieand a spring for each cam positioned be tween one wall of said hollowdie. and the respective turned-up portions for giving the cams acontinuous tendency to move against the hollow die for locking the dieagainst a return movement.

7 In a piano hammer forming machine a pair of dies, a guide barextending from one of said dies, said bar slidingly extending throughthe other die, said other die being hollow, a cam associated with eachof said guide bars for looking the dies against separation after havingbeen moved to a clamping position, said cams extending into said hollowdie, a spring acting on each of said cams and on one wall of said hollowdie for giving the cam a continuous tendency to move toward the hollowdie whereby the hollow die is locked against a return movement, meansfor holding the base of a piano hammer strip so that said dies may pressthe outer felt against the same, and power means for moving said dies toa clamping position, said dies with the strip clamped thereby beingbodily I removable from the supporting and clamping means while in aclamping position, whereby said supporting and clamping means may beused for a second operation immediately after the dies have been movedto a clamping posigo tion.

WILLIAM J. PFRIEMER.

